This research is aimed at an elucidation of some important structural features of the bacterial ribosome. Of principal interest are the relative locations of the ribosomal proteins and the proximities of these to important functional sites. In addition to structural information, we hope to obtain a more detailed picture of the mechanism of protein synthesis. Included in this is the mode of action of several common antibiotics. Simple chemical modification techniques afford information on topography of ribosomal proteins. Affinity labeling is used to identify proteins in particular functional sites. Photoaffinity labels permit the structure of sites to be examined at specific stages in protein synthesis. Singlet - singlet energy transfer is used to measure distances between appropriate fluorescent-labeled ribosomal proteins. Individual fluorescent proteins are reassembled to give single or double fluorescent labeled ribosomes. Other markers can be introduced by preparing functionally active fluorescent factors, substrate analogs or antibiotics. Solvent sensitive probes and external quenchers can provide additional information to supplement results obtained by energy transfer.